Friedel-crafts treatment of unsaturated polymers



Patented July 10, 1951 FRIEDEL-CRAFTS TREATMENT OF UNSATURATED POLYMERSJohn D. Garber, Crani'ord, N. J., assignor to Standard Oil DevelopmentCompany, a corporation of Delaware No Drawing. Application December 28,1946, Serial No. 719,112

This invention relates to synthetic polymers; relates particularly tomethods for the improvement of the physical properties of syntheticpolymers; and relates especially to treatment of moderately highmolecular weight polymers by a solution of aluminum chloride to increasethe 8 Claims. (Cl. 260-853) melting point and hardness thereof withoutsi nificant change in molecular weight. A considerable number ofsynthetic polymers has been prepared, both by a low temperaturetechnique using Friedel-Crafts catalysts and an emulsion technique usingperoxide catalysts, and these polymers show many valuable properties,espeeially'as components of varnishes and paints. However, many of theoil soluble resins so made tend to have undesirably low melting pointsand tend to be unduly soft.

It is now found that if such polymers are treated with aluminum chlorideor other Friedel- Crafts metal halide, an increase in hardness andmelting point may be obtained, either with no change in molecularweight, or, in some instances, with' a minor increase in molecularweight. Such treated polymers remain soluble in oils and, when mixedwith the drying oils, yield faster drying, harder and markedly superiorfinished coating materials.

The process is particularly applicable to the polymers of a majorproportion of a multiolefin having from 4 to about 14 carbon atoms, suchas butadiene with a minor proportion of a mono olefin having 3 or moreup to about carbon atoms prepared at temperatures between -35 C. and +15C. Diene copolymers of butadiene, isoprene, dimethyl butadiene,chloroprene, cyclopentadiene, terpenes may be similarly used, as

well as poly terpenes, poly isoprene, and other poly dienes. Thetreatment is also particularly applicable to. the oily polymers andcopolymers of the multioleflns prepared by an emulsion technique such asin water in the presence of dissolved soap and a dissolved peroxidecatalyst in which the character of the polymer is modified by thepresence of interfering agents such as the mercaptans to yield an oilypolymer or a very soft, semi-solid polymer. The treatment may also beapplied to highly unsaturated polymers and to copolymers of dienes andolefins made by sodium polymerization.

Thus the process of the invention increases the melting point, hardnessand stability of a polymer containing a high proportion of multiolefinsby a treatment with a Friedel-Crafts catalyst in solution. Other objectsand details of the invention will be apparent from the followingdescription:

One of the preferred raw materials for the present invention is the lowtemperature polymer 'of a major proportion of a multiolefln such asbutadiene, isoprene, the terpenes, dimethyl buta-. diene and the likewith a minor proportion of a mono olefin such as propylene, isobutylene,diisobutylene, pentene-2, styrene, and the like. Tertiary base olefinsare preferred as comonomers since good yields of soluble products andhigh catalyst efiiciencies are more readily obtained, as shown in thecopending applications of Sparks & Thomas, Serial No. 414,682 filedOctober 11, 1941 (now abandoned); or the application of Garber, Young 8:Sparks, Serial No. 604,350 filed July 11, 1945; or Serial No. 605,331filed by Sparks 8: Garber on July 17, 1945 (now abandoned), or SerialNo. 606,445 filed by Tracy on July 21, 1945 (now U. S. Patent 2,554,280)or Serial No. 638,514 filed by Sparks and Garber on December 29, 1945(now U. S. Patent 2,546,020). These applications show various aspects ofthe preparation of a low temperature copolymer of a major proportion ofa multiolefin such as butadiene with a minor proportion of anormalolefin having from 3 to 20 carbon atoms per molecule or an isoolefin having 5 to 20 carbon atoms per molecule by the use of dissolvedaluminum chloride as a catalyst at temperatures ranging from about -35C. up to about +15 (J., and the disclosures of all of these applicationsare herewith incorporated into and made a part of the presentapplication. This polymerization procedure yields a resin which is notan elastomer. Instead, it is a light-colored, hard resin which is hardenough to show a conchoidal fracture and a melting point usually betweenand C. (by the ball and ring method). The resulting polymers, as is wellshown in the above-mentioned cross references, are readily soluble inthe various paint and varnish oils including linseed oil, tung oil,oiticia oil, dehydrated castor oil, and the like, and, when so dissolvedmay be given the customary varnish cook to yield excellent paint andvarnish compounds.

According to the present invention, such resins are dissolved in alow-freezing solvent such as methyl chloride, and while in solution, aretreated with a solution of aluminum chloride, BF3, T1014, or certaincomplexes in methyl chloride, or they may be dissolved in a hydrocarbonsuch as i-pentane and treated with a solution of AlBra in isopentane.This treatment does not increase the molecular weight, but does increasethe hardness and strength of the resin with only minor changes insolubility. The reaction is conveniently carried out at temperatureswithin the range between about 50 C. and +100 0., depending upon thesolvent chosen, since it is preferable to conduct the reaction atatmospheric pressure and a convenient procedure conducts the reaction atboiling points of the solvent. .The reaction is quite rapid and may becomplete in from a minute or two to one or two hours and only rarely isthe time required greater than two or three hours, although, withcertain catalysts and at very low temperatures the reaction may requirefrom 12 to 24 hours. It is essential that too great an excess ofcatalyst be avoided, since partial insolubllization of the polymer mayoccur. treatment has reached the desired stage, the material may bepoured into warm water to vaporize out the methyl chloride and tohydrolyze the aluminum chloride, or the mixture may be poured into warmnaphtha to vaporize out the solvent, and then washed with water toobtain a very thorough removal of the aluminum halide residues. Thelatter procedure is particularly advantageous in view of the fact thatthe reactlon sometimes produces small amounts of insoluble matter, whichmaterial is readily filtered out from the naphtha solution. Havingfiltered the naphtha solution, it is then convenient to make afractional precipitation of the soluble polymers, by the addition ofoxygenated solvents such as alcohols or ethers or aldehydes, the firstfraction precipitated showing the highest meltingpoint and the higheststrength. By this procedure, the portion first precipitated may be usedand subsequent portions may be reprocessed to raise the melting pointstill higher.

The dry resin is conveniently recovered by flashing off the solvent in ahot coil, as disclosed in Serial No. 662,693, filed April 17, 1946 byGarber, Sparks and Young, now U. S. Patent 2,507,100.

An alternative raw material is an oily multiolefinic polymer prepared asshown in Serial No. 637,782 filed December 28, 1945 by Frolich,Vanderbilt and Swaney, now U. S. Patent 2,500,983, showing thepreparation of an oily or liquid type polymer by an emulsionpolymerization process in the presence of an emulsifier, a peroxidecatalyst and a polymerization modifier such as an aliphatic mercaptan.This polybutadiene, polyisoprene, polydimethyl butadiene orpolypiperylene or the like similarly may be dissolved in a convenientsolvent such as ethyl or methyl chloride or propane, pentane or hexaneor the like and treated with an aluminum halide in solution, as aboveindicated, whereupon there is obtained a hard resinous polymer which maybe carried to the stage of insolubility, if desired, but is usuallystopped at a point where the resulting hard resin is still soluble inspirit and oil solvents; the process being substantially the same asthat above pointed out.

The process is applicable to many other soft polymers. Copolymers ofdienes such as butadiene, isoprene, dimethyl butadiene, piperlyene withpropylene, butenes, isobutylenes, pentenes, cyclohexenes made bypolymerizations with sodium are highly satisfactory.

Broadly the process can be applied to any unsaturated polymer. Thepreferable type of carbon-carbon double bonds are primary (side vinyl)though cyclic, secondary and tertiary double bonds are also reactive. Inaddition to the hydrocarbon polymers, oxygenated polymers "may besimilarly treated. Thus diallyl phthal- When the ate either as a monomeror partially polymerized may be hardened by treatment with BFa.

Thus the process of the present invention dissolves a, soft oroily typeof unsaturated, olefinic polymer in an inert solvent, and treats it,while in solution, with a solution of aluminum chloride or otherFriedel-Crafts catalyst to increase the hardness and melting point ofthe resin without an increase in molecular weight, and without theproduction of any substantial amount of insoluble material.

The resulting resin is particularly valuable as a varnish gum since itcooks exellently with linseed oil and the other drying and baking oilssuch as tung, octicia, soybean, dehydrated castor, chia, or unsaturatedhydrocarbon drying oils. The treated polymers have many other uses suchas in molding compositions with or without fillers, pigments, colorants,dyes, metallic inserts, and the like; They are also good in admixturewith rubber for tires, proofed fabrics, motor mountings and the like andalso as plasticizers for rubber, admixed with asbestos and a drying oilto make brake linings, in linoleum, etc.

EDIAMPLE I A solution was prepared consisting of an oily butadienepolymer made by the emulsion process above described, in a concentrationof 15% in methyl chloride. This solution was then divided into threeequal portions, which were respectively treated at 20 C. by varyingamounts of a solution of aluminum chloride in methyl chloride During thetreatment the temperature of 20 C. as well as the concentration ofpolymer and diluent were maintained constant by the use 01 a refluxcondenser cooled by solid carbon dioxide At the close of the reactionperiod of approximately 20 minutes, the hardening reaction was halted bydischarge into a large volume of water.

It will be noted from Table 1 that there was recovered from thesolution, upon addition to water, only an oil when no aluminum chloridesolution was added, which oil in solution in diisobutylene showed anintrinsic viscosity of 0.102, corresponding to a. Staudinger molecularweight value of less than 5,000. It will be further noted that theaddition of 430 cos. of aluminum chloride solution yielded after 20minutes a precipitate which was a solid having an iodine number (by theWijs method) of 327, as compared to 397 for the untreated oil; and anintrinsic viscosity in diisobutylene solution of 0.107 indicating astandinger molecular weight number of less than 5,000; not significantlydifferent from the molecular weight of the untreated oil. In sharpcontrast, the substance recovered from the treated solution showed amelting point (by the ball and ring method) of C., as compared to theoriginal oily polymer which had a melting point below room temperature.Similarly, the use of EXALLPLEZ A portion of a low temperaturebutadiene-dilsobutylene copolymer conta approximately equal proportionsof the two components was prepared by the low temperature polymerizationmethod above disclosed and dissolved in methyl chloride to yield a 35%solution by weight. This solution, containing 800 g. resin and 1.500 g.MeCl,

was treated with two portions of aluminum chloride in methyl chloridesolution having a concentration of 0.96%, as shown in Tabe 2. Sampleswere removed at the end of each catalyst addition, water washed anddried as described below:

Table 2 Softening Total Vol.

Point Added of (Ring and Ball) Intrinsic Viscosity tion withouttreatment by aluminum chloride showed a softening point of 72 C.; thepolymer treated with '15 parts of 0.96% of aluminum chloride solutionshowed a softening point of 85 C., and when treated with 150 parts, asoftening point of 95 C.

EXAMPLE 3 Samples of the polymer treated and recovered as in Example 2were dissolved at "15 gallon length," that is, in an approximately equalweight of linseed oil, and cooked at 560 F. to prepare a varnishcomposition. Driers to the extent of 0.05% cobalt and 0.5% leadnaphthenates were added to each varnish cook after thinning with anequal amount of light naphtha. Films of these varnishes were then caston panels, some of which were air-dried for 48 hours, and some werebaked for one hour at 125 C. The cooking time, the time to dry to atack-free condition, and the hardness after drying are shown in thefollowing Table v3:

6 It will be noted that the aluminum chloride treatment sharply reducedthe time required for the varnish to dry to a tack-free condition andvery substantially increased the hardness; with only minor changes inthe required cooking time. This procedure thus permits of thepreparation ofa synthetic varnish resin under conditions of minimumcost, and the hardening and improving of that resin to make an extremelyeffective varnish which dries to films 0! good strength. good hardnessand excellent resistance to deteriorating influences generally. Also,the process permits of a modification of the resins to reduce theirreactivity and avoid the tendency towards excessive oxidation andembrittlement during the life of a varnish film prepared therefrom.

EXAMIPLE4 A copolymer of trimethyl ethylene and isoprene was prepared atlow temperature by the method above outlined involving the treatment ofapproximately equal parts of the two monomers in solution in two volumesof methyl chloride; polymerizing the mixture by the application ofapproximately volume of a 2% solution of aluminum chloride in ethylchloride; the

reaction being conducted at a temperature of approximately 18 C. byexternal refrigeration. The polymerization was carried by approximately45% conversion and the reaction mixture was then diluted withapproximately two volumes of light naphtha to drive out the unreactedmonomers, the diluent and solvent and produce a naphtha solution ofpolymer. The naphtha solution was-then washed in water, dried withcalcium chloride and filtered to yield a naphtha solution containingapproximately 21% non-volatile material. This solution was then dividedup into several portions and the respective portions were treated with a5% aluminum bromide solution in dry naphtha while vigorously agitated.Varying amounts, as shown in the following Table 4 were used and thereaction was allowed to continue for approximately 30 minutes in eachinstance. The reaction temperature was maintained at +35 C. by means ofa jacket surrounding the reactor. At the end of the treatment time, thevarious solutions were washed with water, the naphtha stripped out withsteam, and the product dried in a vacuum oven. The results are shown inTable 4.

Table 4 Volume Softening g of Point Iodine Run Polymer Camyst 0 NumberSolution (Ring Solution (5% and (W) (21%) AlBl'z) Ball) Cc. Ce.

I Did not melt. Insoluble.

It will be noted from this table that a very substantial improvement inmelting point is obtained together with a sharp reduction in iodinenumber. The last fraction was highly crosslinked and hence relativelyuseless in surface coating composition. However, some use as adispersion coating or in molded objects is indicated.

parts of styrene was prepared in the form of a moderately viscous oil bythe emulsion technique above outlined, and after separation from theemulsion form by coagulation, the resulting oil was diluted with threevolumes of methyl chloride and treated with one volume of a 2% solutionof aluminum chloride in ethyl chloride. The polymer recovered wasdefinitely much more viscous than the original polymer oil. It waspurified by washing with water and vacuum drying.

merizate as the raw material EXAMPLE 7 A substantial portion ofsodium-polymerized butadiene containing 10% isobutylene in the copolymerwas dissolved in methyl chloride (20% solution) and treated withseparate portions 01' an AlCla-MeCl catalyst (0.85%) as above. Sampleswere removed after each catalyst addition, quenched in naphtha, waterwashed and dried. The final solids content was adjusted to 50% in eachcase and 0.05% Mn and 0.50% Pb naphthenates added. Films were cast andFilms of the original oil and the treated oil evaluated as follows:

C 1 Air Dried Baked 535,? Gardnep (24 Hrs.) Films 1 Hr.@ 125 0. FilmsRuns Pgrceit vfiiolditt ase 8005 3' On Oil Water Soap Grease Water SoapGrease gg? 0 A s 7 4 s 1 1 0 u 0.5 0 7 7 4 e o 1 0 o 1.0 F s s 5 2 o 1 oo 1.5 R 1 2 5 1 0 0 o o were laid down on sheet metal panels after theadditionof 0.05% cobalt naphthenate and 0.5% of lead naphthenate. Thesepanels were then baked for five hours at 150 C.

The unprocessed polymer yielded a film which on baking was extremelybrittle and readily fiaked off from the panel. In sharp contrast, thetreated oil gave aflexible adherent filmof high strength and very lowbrittleness. It is now considered that the difierence is due to thereduction in reactivity of the oil by the aluminum chloride treatmentand the consequent reduction in the amount of oxidation occurring.

EXAMPLE 6 A butadiene oil was prepared by sodium polymerization andafter separation from the catalyst and unchanged monomer, was dissolvedin five volumes of methyl chloride; cooled to -20 C., and treated with5% of aluminum chloride (based on the amount of oil taken) added in theform of a 1% solution in methyl chloride. The reaction was allowed tocontinue for minutes and was then arrested by the addition of asubstantial amount of isopropyl alcohol. The precipitate was found to benot an oil, but a resin having a softening point of 110 C. This productwas then dissolved in a sufiicient quantity of the original, untreated,oil to make a gallon length varnish. This varnish was cooked at 400 F.until a good, heavy body was obtained, at which point the varnish wasthinned with light naphtha, lead and manganese dryers were added, thevarnish laid down on metal panels, some of which were air-dried andothers baked to yield the following test results:

A rating scale of 0 to 9 was used, 0: unaifecte or excellent, 9:completely removed.

It may be noted that the use of sodium poly- In the above evaluations,resistances to various reagents is rated from 0 to 9, 0 being unaffectedor excellent and 9 being complete removal or very poor.

In the above run the oil was progressively thickened by treatment withAlCla until it resembled a cooked varnish. In other words, the resincomponent was formed in situ, and a varnish composition was preparedwithout the need 01' the lengthy cooking operation that is usuallyrequired.

Thus the process of the present invention modifies an unsaturatedpolymer by treatment with a soluble Friedel-Crafts catalyst to reducethe iodine number and increase the melting point without significantchange in molecular weight to yield a harder, tougher, more durablevarnish either as such or in solution in a vegetable or.

hydrocarbon drying Oil.

While there are above disclosed but a limited number of embodiments ofthe process and product of the present invention, it is possible toproduce still other embodiments withog 'fi; departing from the inventiveconcept herein disclosed and it is therefore desired that only suchlimitations be imposed on the appended claims as are stated therein orrequired by the prior art.

The invention claimed is:

1. The chemical process consisting essentially in dissolving in about 15to 35% concentration in an inert solvent a viscous to solid moderatelyhigh molecular weight polymerization product selected from the groupconsisting of polymers of a multi-olefin having 4 to 14 carbon atoms,and copolymers of at least 50% of such multiolefins with a comonomerselected from the group consisting of a mono-olefin having 3 to 20carbon atoms and styrene, and treating the resulting solution with 0.1%to 10% of a Friedebcraits active metal halide catalyst, in the absenceof any polymerization monomers, at a temperature of 50 C. to C. to raisethe melting point and improve the toughness of said polymerizationproduct without significant change in molecular weight.

2. Process according to claim 1 in which the after-polymerizationFriedel-C'rafts treatment is carried out at -20 to +35 C.

3. Process according to claim 1 in which the 9 after-polymerizationFiiedel-Crafts treatment is carried out at about 15 C. to -20 C.

4. The chemical process consisting essentially in dissolving in about 15to 35% concentration in an inert solvent, a solid, resinous, moderatelyhigh molecular weight polymerization product consisting essentially of acopolymer of at least 50% of a multi-olefin of 4 to 6 carbon atomswithnot more than 50% of an isomono-olefin of to 8 carbon atoms, andtreating the resulting solution with 0.1% to 10% of a Friedel-Craftsactive metal halide catalyst in the form of a solution thereof in aninert solvent, in the absence of any polymerization monomers,,at atemperature of about -20 C. to 35 C., to raise the melting point andimprove the toughness of said resinous polymerization product withoutsignificant change in its molecular weight.

5. The chemical process consisting essentially in dissolving, in aboutto 35% concentration, in an inert solvent, a solid, synthetic,hydrocarbon resinproduct by copolymerization of about equal amounts ofbutadiene and an iso-monoolefin of 5 to 8 carbon atoms at 35 C. to 15 C.with a Friedel-Crafts catalyst, said resinous polymerization producthaving been separated from unreacted monomers and having a melting pointof about '70 to 120 C. by the ball and ring method, and treating theresulting solution with 0.1% to 10% of aluminum chloride in the form ofa solution thereof in an alkyl chloride of 1 to 2 carbon lar weight.

6; Process according to claim 5 in which the iso-mono-olefin isdiisobutylene, and the afterpolymrization heating temperature is about7. A tough resinous product derived by chemical treatment of a solid,resinous, polymerization product consisting essentially of acopolymer of10 at least of a multi-olefinof 4 to 6 carbon atoms with not more than50% of an iso-monoolefin of 5 to 8 carbon atoms, said resinouspolymerization product having a melting point of about to 120 C. by theball and ring method, said resinous product having been treated afterpolymerization, in the absence of any polymerization monomers, in about15 to 35% concentration in an inert solvent, with 0.1% to 10% of aFriedel-Crafts active metal halide catalyst, at about 20 C. to 35 C. toraise the melting point and improve the toughness of said resinouspolymerization product without significant change in its molecularweight.

8. A tough hydrocarbon resin having a melting point of about C. by theball and ring method, which has been derived by an afterpolymerizationchemical treatment of a resinous polymerization product having a meltingpoint of about 72 C., and consisting essentially of a copolymer of aboutequal amounts of butadiene and diisobutylene, said resinouspolymerization product having been subjected to an after-polymerizationchemical treatment, in solution in about 15 to 35% concentration in aninert solvent, in the absence of any polymerization monomers, with 0.1%to 10% of aluminum chloride, in the formof a solution thereof in analkyl chloride of 1 to 2 carbon atoms, at a heating temperature of about20 C.

. JOHN D. GARBER.

REFERENCES CITED The followlngreferences are of record in the 35 file ofthis patent:

UNITED STATES PATENTS Sparks et a1. Oct. 12, 1948

1. THE CHEMICAL PROCESS CONSISTING ESSENTIALLY IN DISSOLVING IN ABOUT 15TO 35% CONCENTRATION IN AN INERT SOLVENT A VISCOUS TO SOLID MODERATELYHIGH MOLECULAR WEIGHT POLYMERIZATION PRODUCT SELECTED FROM THE GROUPCONSISTING OF POLYMERS OF A MULTI-OLEFIN HAVING 4 TO 14 CARBON ATOMS,AND COPOLYMERS OF AT LEAST 50% OF SUCH MULTIOLEFINS WITH A COMONOMERSELECTED FROM THE GROUP CONSISTING OF A MONO-OLEFIN HAVING 3 TO 20CARBON ATOMS AND STYRENE, AND TREATING THE RESULTING SOLUTION WITH 0.1%TO 10% OF A FRIEDEL-CRAFTS ACTIVE METAL HALIDE CATALYST, IN THE ABSENCEOF ANY POLYMERIZATION MONOMERS, AT A TEMPERATURE OF -50* C. TO 100* C.TO RAISE THE MELTING POINT AND IMPROVE THE TOUGHNESS OF SAIDPOLYMERIZATION PRODUCT WITHOUT SIGNIFICANT CHANGE IN MOLECULAR WEIGHT.